230 THE AMERICAN CHARACIDAE. 



Key to the Species. 

 Subgenera: Pocciluriclithys and Zygogaster. 



a. Lateral line 40-55, sometimes 38 in abramis. 

 b. Anal rays 40-45; mouth very small; rows of scales below the lateral line, deflected toward anal; 

 caudal spot not continued to end of caudal. (La Plata Basin). 

 c. Lateral line 48-55. 

 d. Depth 2.63; A. 45; lateral line 55; eye .66 in snout, .S-.S3 in interorbital. 



1. crythrojiterus (Holmberg). 

 dd. Depth 2-2.2; A. 40-45; lateral line 48-50; eye 1-1.1 in interorbital, 2.75 in head; inter- 

 polated rows of scales beginning above origin of ventrals. 



2. alleni (Eigemnann & McAtee). 

 cc. Lateral line 42-50. 



e. Depth 2.5-2.8; A. 41; scales 9 to 11^5 to 50-8; eye 1 in interorbital, 2..5-2.75 in head; 



interpolated scales above anal only 3. pellegrini Eigenmann & Kennedy. 



ee. Depth 2.5; A. 45; scales 8^2-7 or 8; eye 1.7 in interorbital, 3.7 in head. 



4. corrcntinus (Holmberg). 

 66. Anal rays 34-43. (Ecuadorian species) . 



/. Maxillary without teeth, about half as long as eye; two conspicuous humeral spots; no 

 caudal band, the spot variable. Depth 2.5-3; A. 33-40; scales 8-41 to 47-8; eye 



2.75 in head, equals interorbital in largest 5. festae (Boulenger). 



ff. Maxillary with two teeth, about half as long as snout and eye; a distinct humeral .spot; 



depth 3; A. 41; scales 8-46-8; eye 2.5 in head 6. rweli Pellegrin. 



666. Anal rays 22-34; mouth large; maxillary about equal to the eye. 



g. No humeral spot; very few short auxiliary rows of scales above the anal; 2-4 striae 

 on the scales above the lateral line; depth 2 7/11-3.3. (Upper Amazon). 

 h. Scales 11 or 12-54 or 55-9 or 10; A. 28-32; depth 3-3.33; a black spot on the base 

 of the middle caudal rays, continued to the lower margin of the fin and to near the 



tips of the middle rays 7. anymmctricus Eigenmann. 



hh. Scales 8-48-6; A. 30; depth 2 7/11; a caudal spot continued on the middle caudal 



rays 8. sytmnetricus Eigenmann. 



gg. A round humeral spot over the 7th-9th scales of the lateral line; depth 2-2.5; A. 27-31; 



lateral line 42— 46; interorbital very convex. (Guiana) 9. polylepis (Gunther). 



ggg. A faint vertical humeral spot over the 3d scale of the lateral line. Depth 2.7-3.; 

 scales 8 or 9-42 to 47-5 or 6; A. 27-30; eye 2.56; 2-1 1 striae on the scales above the 

 lateral line; a black or dark bar across the base of the caudal, continued on the 



middle caudal rays 10. zonatus Eigenmann. 



gggg. A well-defined horizontally or vertically oval humeral spot. 



i. Caudal spot not continued to the end of the rays; no spot on caudal peduncle; 

 silvery band narrow and faint. 

 j. Scales 12-53-9; A. 34; humeral spot horizontally ovate over and in part on the 

 first five scales of the lateral line; caudal spot .small, well defined; lower 



fins blackish 11. bourgeti Eigenmann. 



jj. Scales 9 to 11-43 to 51-7; A. 28-30; humeral spot narrowly ovate, horizontal, 

 over the first five scales of the'lateral line, caudal spot large diffuse. 



12. abramoides Eigenmann. 

 ii. Caudal spot continued to the end of the middle rays. 



k. Depth 2.8; humeral spot sublinear, over the origin of the lateral line; scales 

 10-52 or 53-6; A. 28-32; scales not deflected toward the anal. 



13. anterior Eigenmann. 

 kk. Depth 2-2.3; humeral Spot oval; a broad .spot on caudal peduncle, tapering 

 forward; scales 7 to 10-38 to 49-6 or 7; A. 30-34. 



14. abramis (Jenyns). 

 (iu. Scales 40, or fewer, except rarely 41, in A. bimaculalus, A. caucanus, and A. stilbe. 



I. A well-defined circular or horizontaUy oval humeral spot; A, 21-41; scales 

 31-41. V-cSfl 

 VI. Depth less than 3 in the length. 



